# What are the methods of threshold homomorphic decryption？

**URL:** <https://openfhe.discourse.group/t/what-are-the-methods-of-threshold-homomorphic-decryption/932>\
**Category:** FHE Questions\
**Tags:** questions\
**Created:** [November 22, 2023, 1:26am UTC](https://openfhe.discourse.group/t/what-are-the-methods-of-threshold-homomorphic-decryption/932 "2023-11-22T01:26:07Z")\
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**Author:** ![kenan](https://avatars.discourse-cdn.com/v4/letter/k/e495f1/32.png) [@kenan](https://openfhe.discourse.group/u/kenan)\
**Post date:** [November 22, 2023, 1:26am UTC](https://openfhe.discourse.group/t/what-are-the-methods-of-threshold-homomorphic-decryption/932/1 "2023-11-22T01:26:07Z")

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How is threshold homomorphism decrypted in practical use, that is, how does the server decrypt it? Is it to obtain everyone’s private key, or to act as a proxy to re encrypt and decrypt it? I don’t know how the Analytic of Multiparty (threshold) FHE to decrypt in this Collaborative Privacy Resilience Analysis of Online Data Using Multiparty Homomorphic Encryption ?

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**Author:** ![Caesar](https://yyz1.discourse-cdn.com/flex031/user_avatar/openfhe.discourse.group/caesar/32/63_2.png) [@Caesar](https://openfhe.discourse.group/u/Caesar)\
**Post date:** [November 24, 2023, 5:46pm UTC](https://openfhe.discourse.group/t/what-are-the-methods-of-threshold-homomorphic-decryption/932/2 "2023-11-24T17:46:11Z")

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In threshold-based multiparty fully homomorphic encryption (FHE), the involved parties, who collectively hold the secret key shares, collaborate to decrypt a ciphertext through a distributed decryption protocol. This process can be likened to incremental decryption, where each party contributes a portion of the decryption, and the combined partial results yield the complete decryption. While a server or one of the parties can serve as the aggregator, the secret key shares never leave their respective owners’ possession, ensuring a secure and distributed decryption process.

This [work](https://eprint.iacr.org/2020/304.pdf) presents an example of multiparty FHE schemes that employ an additive-structured secret-shared secret key.